5G8 NEW SPECIES OF PARASITIC COPEPODS. 



indented sides. Upon contraction in alcohol the outline changes greatly, 

 the width becoming' nincli rodiicod Jinteriorly, the sides sliglitly sinuous 

 and diverging: more or less rapidly Ironi the head backwards, as repre- 

 sented in Fig. 4, J'late XXXIIL 



There are no indications of segmentation or divisions on the dorsal sur- 

 face back of the cephalothorax, except such as result from the indenta- 

 tions of the margins. JJack of the thorax, last above described, is a 

 large, broad, dorsal shield, from the ventral surface of which, near the 

 front, arise the thoracic feet of the fourth pair, precisely as in L. Brevoor- 

 tiic. The lateral margins of this division of the body are not indented, 

 however, in living specimens, and very rarely in alcoholic ones. In the 

 former it is oblong or broadly subovate in outline, with the posterior mar- 

 gin rounded or straight, the greatest width, which is generally less than 

 that of the thorax, being near the middle. At the front, where it joins 

 the thorax, the body is abruptly constricted ou the sides, as shown in 

 the several general views. In alcoholic specimens the dorsal shield is 

 widest near the front, whence the sides, which are sometinu^s slightly- 

 indented near the middle, converge toward the posterior end, the latter 

 being cut off more or less squarely. The cei)halothorax and thorax do 

 not differ much in length, but the dorsal shield is somewhat longer than 

 either, and both the thorax and shield, whatever their shapes may be, 

 are generally considerably wider than the cephalothorax. 



In side view the cephalothorax appears thick, especially uear the 

 front, where the sides are more or less extended in a square or rounded 

 lobe, as shown in Fig. 2, Plate XXXIIL In ventral view the cheeks are 

 shorter and broader than in L. BrevoorUw, not extending backward much 

 beyond the middle. The thorax proper is relatively stout, as is also the 

 median portion of the dorsal shield as far down as the fourth pair of 

 feet and the abdomen, but towards the margins the dorsal shield thins 

 out. In alcoholic specimens, however, the latter segment becomes 

 greatly inflated and bag-like, and its shape is entirely changed. The feet 

 of the third pair are longer, but much narrower than in Jj. Brcvoortkv. 

 They appear not unlike short sleeves to a man's coat, cut away on the 

 lower side, and directed downward and backward. In alcohol the walls 

 are often so swollen as to entirely close the central opening. They are 

 uot visible at the sides of the thorax in dorsal view. The feet of the 

 fourth pair consist each of two rami, as in L. Breroorfuv, the inner rami, 

 however, being only slightly shorter than the outer, and both very 

 elongate, narrow, thin, generally acute, but sometimes rounded at the 

 tips. They are united near the base, and about two-thirds of their 

 length is exposed beyond the posterior margin of the dorsal shield. In 

 alcohol they become narrower and slightly thicker, and are almost in- 

 variably placed in the symmetrical positions represented in Fig. 4, 

 riatc XXXIIL 



The abdomen is small, sul)circular, or transverse ; the caudal segment 

 elongate, terminating posteriorly in two large, elongate, rather stout. 



