Dr. J. Mmie on the Skin ci-c. of the Rhytina. 313 



own scalpel, Phoccena, Lagejiorhynchus^ Physalus, Grampusj 

 and Globiocephalus^ the skin is tense, smooth, and free from 

 tubercular rugosities, the peculiar longitudinal belly-ridges 

 and furrows and folds of the axillfe being the only marked 

 elevations and depressions. In the Sirenian Manatusj on the 

 other hand, the skin, throughout the entire body, is charac- 

 terized by innumerable transverse, large and lesser wavy 

 grooves and ridges. Moreover, as in some pachyderms, the 

 elephant for example, there are circular and irregular-shaped 

 elevations of derm, giving a rough warty appearance to the 

 skin. These elevated areas in the Manatee are distributed 

 here and there, but are particularly pronounced about the 

 head, shoulders, and outer surface of the fore limb. That 

 they existed with something of the same distribution and 

 pattern in the Rhytina I infer from Steller's exact description ; 

 only in that animal they of course would be proportionally of 

 greater magnitude. That the parasites would cause a certain 

 amount of irritation I am prepared to admit, but cannot at all 

 believe that to their ravages alone the dermal excoriations 

 of the corneous Bhytina-skin are due. 



My own views regarding the relations of Rhytina towards 

 other Sirenia, the Cetacea, and Pachydermata I treat of in my 

 forthcoming memoirs on Manatus and Halitherium. 



EXPLANATION OF PLATE XLK. 



Fig. 1. Copy of Dr. Alexander Brandt's figure of the piece of Rhytina's 

 skin found by liim in the St.-Petersburg Museum. The illus- 

 tration has been talcen from a photograph of the original speci- 

 men, reduced to one fifth of its natural dimensions. It represents 

 the outer surface. 



Fig. 2. This shows a portion of the skin" of Rhytina as I have delineated 

 it in my representment of the animal. Faithfully following 

 Steller's description, and applying my knowledge of the skin of 

 Manatus and HaUcore, I have produced, mthout a knowledge 

 of Brandt's paper, an epiderm almost identical with his photo- 

 graph. That here shown is from the region of the back, above 

 and behind the fore limb. 



Fig. 3. A view in part of the upper third of fig. 1, but of natm-al size. It 

 exhibits the peculiar protuberances and clefts, Vhich are even of 

 greater magnitude at the lower end of the specimen, where, as 

 Brandt has delineated {loc. cit. figs. 4 & 5), the elevations elon- 

 gate and rim into one another, whilst the fiu-rows of more regular 

 continuity have here and there hairs springing from them. 



Fig. 4. A vertical section of the skin, of natural magnitude, and display- 

 ing its columnar-like character. After A. Brandt, who states 

 it is a piece torn by the finger-nail from the skin after being 

 partially softened. 



Fig. 5. Under surface of the female Cyamus Wiytince (Brandt), nat. size. 



Fig. G. Upper surface of the male of the same species, nat. size. 



Fig. 7. A magnified \'iew of the male parasite from the Rhytina, as deli- 

 neated by Brandt ; abdominal aspect. 

 Ann.itcMwj'.Nat.IUat. Scr. 4. Vol.ia. 22 



