1876.] ANATOMY OF PLOTUS ANHINGA. 343 



partment] about half an inch in diameter, which is lined with bristly 

 hairs. They are all inserted at right angles to the surface, penetrate 

 to the base of the epithehuni, and are of various lengths, some of 

 them not protruding beyond the surface, others upwards of half an 

 inch, of various colours, some black, generally tipped with whitish, 

 others light greyish yellow, all thick at the base, and tapering to a 

 fine point. Being disposed in a regular manner, they might seem to 

 for^n a part of the organization of the stomach, and not to be, like 

 the hairs fouud in Cuculus canorus and Coccijzus americanus, merely 

 extraneous." The pyloric orifice in Plotus anhinga, as is seen in 

 Plate XXVIII. fig. 2," is protected by a mat of lengthy hair-like pro- 

 cesses, much like cocoa-nut fibre, which nearly half fills the second 

 stomach. This second stomach is globose, and nearly an inch in 

 external diameter. Its dense lining-membrane is raised into short 

 rugae and tubercles, as is that of the first ; and it is evidently a 

 modification of the epithehum which develops these tubercles in 

 the region of the pylorus which gives rise to the above-mentioned 

 mat-sieve. The hairs composing the mat are hispid, slender, and 

 about half an inch long. They arise from a surface a little less than 

 a square inch in area round the pylorus, which is in its centre. 

 They cease at the very margin of the small circular orifice, where 

 the commencement of the delicate mucous membrane of the duode- 

 num can be just seen. My friend, Mr. E. A. Schiifer, Assistant Pro- 

 fessor of Physiology at University College, has very kindly examined 

 these hairs microscopically, and tells me that " they are much more 

 like true hairs, both in structure and mode of attachment, than they 

 are like the epithelial projections which are so often met with over 

 the fihform papillae of the human tongue, which, at first sight, they 

 much resemble. Like hairs, they consist of an outer ' cuticular ' part, 

 and an inner ' fibrous ' part ; and in some places there is also yet 

 another substance running along the middle of the fibrous part, 

 which might be compared to the medulla of a hair. The cuticular 

 part is much thicker in proportion than that of a cutaneous hair, and 

 forms here and there dentate projections at the sides of the filament. 

 The cuticle is continuous with the horny superficial portion of the 

 stratified epithehum which covers this part of the stomach ; in neither 

 can the outlines and nuclei of the component cells be distinctly seen, 

 the cells having blended into a nearly homogeneous substance. That 

 portion of the hair which extends below this into the deeper layers 

 of the epithelium, appears not to be covered with a prolongation of 

 the cuticle, but to be formed only of the fibrous part. This last- 

 named seems, like the fibrous or cortical constituent of a cutaneous 

 hair, to be composed of a closely set bundle of much elongated cor- 

 nefied epithelial cells, slightly larger than those of a cutaneous hair, 

 and with their extremities uot fusiform (as in that) but truncated. 

 The number in a cross section varies according to the size of the 

 filament. They may, in many, be seen projecting at the end a little 

 beyond the cuticular part. 



" The roots of the gastric hairs are so closely set as to occupy the 

 greater portion of the mucous membrane, so that the connective 



