478 ZOOLOGY. 



two species — G. cornutus and C. Agassizii, tlie former occurring in 

 ditches in the-rice fields of South Carolina, while the latter is only 

 known from a specimen found in a well in Lebanon, Tcnii. A third 

 species of Chologaster * has recently been added by Prof. S. A. Forbes, 

 and was discovered in a spring at the foot of a bluff in western 

 Union County in the southern part of Illinois. At first only one 

 specimen was obtaiued and a name was deferred till more information 

 should be obtained. Later,! seven more specimens were secured and the 

 form has been named Chologaster papilliferus. The species is especially 

 noteworthy in that it lessens the gap between its own kind and the blind 

 fish and answers one of the objections urged against the primitive com- 

 mon parentage of all the species. 



Habits of fierasfer. 



In certain of the holothurians (known as sea-cucumbers, trepangs, 

 &c.), living at moderate depths, fishes may be found in the interior of 

 the body. These fishes are elongated and taper to the end of the tail, 

 which is pointed. The name of fierasfer has been given to them. 

 How they enter into the holothurians has been explained by Pro- 

 fessor Emery. When free in the water, the fish swims head down- 

 wards with tail curved toward the back, by undulatory movements 

 of the anal fin. Coming to a holothurian lying at the bottom of the 

 water, it eagerly seeks the posterior aperture. Sometimes it pene- 

 trates through this head-foremost, but generally enters in a character- 

 istic manner. By its anal aperture the holothurian expels and sucks 

 in water. The fish, during the expulsion of the water, pushes its head 

 into the orifice and curves its tail to one side, and then by a rapid 

 recoil movement, introduces itself, tail-foremost, into the intestinal 

 canal, pushing farther and farther in with every suction of its in- 

 voluntary host. From the intestine it penetrates into the pulmon- 

 ary passageo, and thence, after their rupture, into the perivisceral 

 space. It remains, however, near the anus, and protrudes its head, 

 when hunger impels, in search of food. It is therefore neither a true 

 parasite, since it does not feed on its host, nor a commensal, as it does 

 not share the food of its host, but simply a lodger or tenant at will. 



AMPHIBIANS. 



Skull. 



Parker (W. K.). On the structure and development of the skull in the Batrachlan. 

 P. Ill, with 44 pi. Philos. Transact. R. Soc. London, v. 172, 1881, pp. 1-266. 



'Forbes (S. A.). A rare fish in Illinois. Am. Nat.^ v. 15, pp. 232-233. 

 tForltcs (S. A.). The blind cave fishes and their allies. Am. Nat., v. 16, pp. 1-5, 

 JaQ., 188-i. 



