kind of distribution few instances are known amongst mammals, but many somewhat similar cases have been observed in birds, reptiles, and butterflies.

The fourth and lowest sub-family of the Cebida (Nyctipithecina) includes three genera―the Douroucoulis (Nyctipithecus), the Titis (Callithrix), and the SquirrelMonkeys (Chrysothrix), and numbers altogether some twenty species. This group, as a whole, has a wide range like the two first sub-families, extending from Central America to Paraguay. But the species are most abundant in the centre of the area, where some of them, so far as is yet known, have a very limited range.

SECTION V.-DISTRIBUTION OF THE MARMOSETS

Like the Platyrrhine Monkeys the little Marmosets, which constitute the family Hapalidæ, are entirely restricted to the tropical forests of the New World. The family embraces but two genera generally acknowledgedHapale with about seven, and Midas with about fourteen or fifteen species. But these small creatures are still little known, and it is probable that many more of them remain to be discovered when the vast forest-region through which they are distributed shall have been more thoroughly explored. The Marmosets do not extend so far north as the true Monkeys, only a single species (Midas geoffroyi) having yet been ascertained to range north of the Isthmus of Panama as far as Chiriqui. Thence, southwards, they are thinly distributed over the South American continent down to the northern provinces of the Argentine Republic, where Hapale penicillata is said to occur in the forests of Salta

and Jujuy. The Marmosets appear to be most numerous in the forests of Amazonia, where some of them are confined to very restricted districts. Our best account of these animals is to be found in the journals of the excellent observer Bates.

SECTION VI-SUMMARY AND DEDUCTIONS

The subjoined table contains a list of the genera of the Order Quadrumana, or Monkeys, and gives the approximate number of species met with in each of the great geographical Regions.

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DEDUCTIONS.

1. The Order Quadrumana, or Monkeys, contains about 212 species, divisible into twenty genera and four families.

2. Monkeys are found only in the tropical and subtropical portions of the Eastern and Western Hemispheres, and are absent in Australia and Madagascar.

3. The Monkeys of the Eastern and Western Hemispheres are quite distinct in structure, and belong to different families. 4. In the Western Hemisphere Monkeys are restricted to the Neotropical Region, not occurring north of 20° N. lat., or south of 30° S. lat.

5. In the Eastern Hemisphere some few species of Monkeys are met with as far north as 40° N. lat., and in Africa descend to 35° S. lat.

6. The Monkeys of the Ethiopian and Oriental Regions belong to distinct genera.

7. The Anthropoid Apes are restricted to the tropics of Africa and Asia, the most highly organized of them being the Chimpanzees of Africa and the Orangs of Asia.

SECTION VII.-DISTRIBUTION OF THE LEMURS

The Lemurs, which by many recent authorities are united with the Monkeys to form the Order Primates, but which it is, in some respects, more natural to retain as an Order by themselves, number altogether some fifty species-only onefourth of the number of the Quadrumana. They are also very different in geographical distribution, thirty-five out of the whole series being confined to the Malagasy Sub-region, whilst the few remaining forms are met with only in isolated portions of the Ethiopian and Oriental Regions. Besides the family of

true Lemurs (Lemurida) this Order contains the two aberrant types, the Tarsier (Tarsius) and Aye-aye (Chiromys), both of them of family value. We will say the few words that are necessary about the distribution of each of these three families.

The typical Lemurs (Lemurida), are usually divided into four sub-families, the Indrisinæ (Indrises), Lemurinæ (Lemurs), Galaginæ (Galagos), and Lorisine (Slow Lemurs). Of these, as will be seen by the annexed table, the two first sub-families, which contain seven genera and about twentyfour species, are absolutely confined to Madagascar and its adjoining islets. It is, in fact, mainly the presence of these peculiar animals, which constitute altogether nearly one half of the whole mammal-fauna of Madagascar, that renders the Malagasy fauna so very different from that of any other part of the world's surface, and makes it a moot point as to whether this zoological division should not be more properly treated as a “Region," than as a "Sub-region." When we come to the third sub-family-the Galagos-we find the typical genus Galago with its six species distributed over continental Africa, but the three other genera of this family, which contains smaller animals of somewhat aberrant form, are again entirely restricted to Madagascar. The fourth and most aberrant group of the Lemurs, commonly called Slow Lemurs, from their nocturnal habits and sleepy dispositions, contains four genera, two of which belong to the Ethiopian Region and two to the Oriental Region. Although they vary considerably in structure from the more typical Lemurs, there can be no doubt that the Slow Lemurs possess a true Lemurine structure in many important particulars, so that they must have had a common origin with the true Lemurs. This fact would seem to show that the ancient "Lemuria," as the hypothetical