1887.] PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 567 



l»;iir of feet, and the mediau ventral frame- work of the cephalothorax 

 are of a ii<;ht horn color, while the proboscis, i^alpi, appendages of the 

 first i^air of thoracic feet, and the entire second thoracic feet arc color- 

 less, and of a very delic;ate textnre. Tlie reniaiiiinq: appendages are like 

 the body in consistency and appearance. The length of the entire body 

 is 5'"™; tlie length of the body, together with the fourth pair of feet, 



'Tnmi 



This species has so far been observed only on the gills of the menha- 

 den, i>reroor<m tyrannns Latrobe, taken in Vineyard Sonnd, JNIassachu- 

 setts, by the U. S. Fish Commission. It is very abnndant at times, and 

 many specimens often occur on a single fish. ISo males have yet been 

 found. The specimens are catalogued as follows in the record books of 

 the Natioual Museum : ()()25, G0G4, COSO, GU9, G170. 



Lernanthropiis Pomatomi Ratbbmi, new species. 

 (Plates XXXIII-XXXV.) 



This species is of about the same size as LernanthropuH Breroortia\ but 

 may be readily distinguished from it by the size and shape of the tho- 

 racic appendages corresponding to the third and fourth pairs of feet and 

 by the contour of the posterior part of the body. Other less conspicu- 

 ous features differ to the same extent, and the two species are very dis- 

 tinct. A number of specimens of the males of this species were obtained 

 with the females and are described below. The original figures, repre- 

 senting the general characters of the animal and the larger appendages, 

 were drawn from living or fresh specimens, and the following description 

 is made up from the same kind of material, unless otherwise expressly 

 stated. By contraction in alcohol the shape of the body and of the softer 

 ai)pendages is greatly changed. 



Female. — A dorsal view of a living specimen is represented in Fig. 3, 

 Plate XXXLII, and the same view of one that had long been i>reserved in 

 alcohol in Fig. 4 of the same plate. In the former the cephalothorax is 

 elongate, narrowest at the front, the lateral margins diverging and gen- 

 erally slightly concave near the middle, but becoming convex and regu- 

 larly rounded near the posterior corners, where the greatest width occurs. 

 The anterior margin is broadly excavated, convex in the middle, and 

 with the corners somewhat prolonged and rounded; the posterior mar- 

 gin is strongly and regularly curved, and may be closely pressed against 

 the anterior end of the thorax or separated from it, according to the state 

 of contraction of the specimen. In alcoholic specimens the front margin 

 remains about the same, but the sides are convex; the greatest width 

 occurs near or in advance of the middle, and the hinder part of the 

 cephalothorax becomes much narrowed and more strongly rouudcd tlian 

 in living specimens, producing a stiboval outline. The thorax forms a 

 square figure, as in L. Brevoortuv, but is proportionately wider and 

 shorter, widest posteriorly, with well rounded corners, ami more or less 



