232 Analytical Notices of Books. 



from the dismemberment of the extensive group of Terehratula. 

 They consist of one of Fishes under the name of Teratichthys^ 

 but the characters of this are not yet sufficiently recovered to 

 establish the genus with accuracy : four of Mollusca^ 1. Phare- 

 irium, probably belonging to the PteropodOy described as a " tes- 

 taceous body, composed of two conical sheaths, one external, the 

 other internal and perforated at its apex, united together near the 

 margin of the mouth ; " 2. Leucopthalmus, a genus of AscidiUy 

 with the " body globose, coriaceous, pedicelled : apertures two, 

 pentagonal, five-rayed ; " 3. Trigonotreta, and 4. Trigonosemus, 

 separated from Terebratula ; a division necessitating the reforma- 

 tion of the characters of the latter genus, which is therefore con- 

 fined to those species in which the rostrum of the produced valve 

 is emarginate or subcanaliculate, and perforated at the apex; while 

 in Trigonotreta this part is perforated, flattened, and subtriangu- 

 lar internally, and is also internally flattened in TrigonosetmiSy 

 the flattened surface having a triangular mark, and the perforation 

 being at the apex ; a new genus of those very interesting fossils 

 the Trilobites^ Homalonotus, a name indicating its most distin- 

 guishing characteristic, the flatness of the back : and two genera 

 of Polypi, 1. Aspidiscus, " orbicular, convex above, furnished 

 with crenulate, unequal, decussating crests ; beneath flat and 

 markfed with circular concentric stria; ; " and 2. Blumenbachium, 

 " globose, externally beset in every direction with stellulae, 

 which are prominent, generally four-rayed, frequently confluent, 

 punctate - porous ; internally cavernous, its substance fibrous- 

 cellular." One other genus, Spongus, requires also to be men- 

 tioned, since the family of which it forms a part is generally 

 admitted into the animal kingdom. It differs chiefly from Spongia 

 in its texture, before it became fossilized, having been much more 

 lax; in its more regular form; and in the evident traces which re- 

 main of its having possessed an evanescent epidermis. 



Annalen des Sciences Naturelles. Nos. xi. and xii. 

 In noticing briefly the leading zoological facts contained in the 

 present numbers of this valuable periodical, an arrangement of the 

 paper? will be pursued corresponding with the location of their 



