154 BULLETIN OF THE 



Family MATUTIDAE. 



The Matutidae may conveniently be divided into two subfamilies, Ma- 

 tutinae and Hepatinae. The latter group differs from the former in hav- 

 ing a broader carapax, a narrow facial region, and short orbits and eyes. 



Subfamily HEPATINAE. 



Osachila nov. gen. 



This genus is allied to Hepatus in all essential characters, but differs 

 considerably in the shape of the carapax, which is nearly as long as broad, 

 and has the front much produced, so much so as to form a true rostrum in 

 one species. The carapax is also more or less depressed and expanded at 

 the sides, and its surface is very uneven, having six chief protuberances. 



Species of this genus are found in the seas of both sides of Tropical 

 America. The name is that of a Florida Cacique. 



Osachila tuberosa nov. sp. 

 Carapax somewhat octagonal, very slightly broader than long ; surface 

 very uneven, deeply pitted on the protuberances, and finely, densely punc- 

 tate on the depressed parts. Three of the protuberances are on the 

 gastric region, and correspond to the metagastric and urogastric lobes, 

 the protuberance of the latter being much the smallest, and continued an- 

 teriorly in the form of a slight ridge in the furrow between the metagastric 

 lobes, reaching, with the furrows, nearly to the frontal region. The cardiac 

 protuberance is rounded and smaller than the metagastric ones. Themeso- 

 branchial lobes are strongly protuberant and larger than the metagastric, 

 and there is a small, elongated, longitudinal protuberance between them 

 and the cardiac protuberance. The front is projecting, and bilobed, with 

 the lobes very obtuse and separated by a deep furrow. No protuberance on 

 the concave hepatic region. Antero-lateral margin straight or slightly con- 

 cave anteriorly, but quickly curving backward and becoming parallel to the 

 axis of the body in the greater, posterior part of its length ; it is armed 

 with numerous small irregular teeth, and is pitted above like the protuber- 

 ant parts of the carapax ; and the posterior tooth, which forms part of the 

 branchial protuberance, is larger than the others. Postero-lateral margin 

 nearly straight, obtuse, rugose, and armed with two or three tuberculi- 

 form teeth, of which one, separated from the posterior extremity of the 

 carapax by a concavity, is the largest. Posterior extremity of the carapax 

 narrow, with a rugose and much-thickened margin concealing the base of 

 the abdomen. Beneath, the entire surface of the carapax, maxillipeds, 

 sternum, abdomen, and of the bases of the feet, is densely covered with 

 rather large pits, giving it a vermiculated or reticulated appearance. 



