INVERTEBRATA, CRYPTOGAMIA, MICROSCOPY, ETC. 255 



the abdomen forms a mere appendage to the end of the body ; the 

 thorax too ceases to present clistinct segments, though the thoracic 

 appendages are still retained. In Lernanthropus, though retained, 

 they are considerably metamorphosed ; the first two pairs only present 

 the characteristic Copepod form, the other two (or three) are con- 

 verted into merely tubular appendages or lobes ; the cephalothoracic 

 region is divided by a deep groove which separates the antennary 

 from the post- antennary portion, and which is probably due to the 

 mode by which these parasites attach themselves to their hosts. 



The body has an elongated, ellipsoidal form, and all indications 

 of regular segmentation are lost, though it is still divided into a 

 number of parts by transverse grooves ; of these the most anterior 

 carries the two pairs of antenufe, together with a pair of processes 

 with broad bases, but rapidly narrowing, and of some length. Behind 

 the base of the first pair of antennae and in the middle line there are 

 four dots arranged in trapezial form, which are the seats of four tactile 

 setJB. This division of the body is connected with the succeeding one 

 by a rod-shaped thickening of the carapace (articular rod), which is so 

 placed as to hinder considerably any lateral movement of the parts on 

 one another or any bending upwards of the anterior one. The next 

 division of the body consists of the fused remaining cephalic and the 

 first thoracic ring; to this the mouth organs and the first pair of 

 rudder-feet are attached. Now follow the fused segments of the 

 thorax, and to them is attached the small abdomen. This region 

 is longer than either of those in front of it, and carries the second 

 pair of rudder-feet, and the two or three metamorphosed tboracic 

 appendages already mentioned ; the anus opens at the hinder end 

 between the two processes of the characteristic Copepod furca. The 

 colour of the animal varies between a dark reddish yellow and a deep 

 reddish brown ; but there are individual as well as specific differences 

 in coloration. 



Owing to their habits the creatures exhibit not only atrophy in 

 the segmentation of the separate appendages, but a loss of all hairs 

 and setfe, while the mouth organs arc converted into sucking and 

 stabbing organs. The second pair of antennje are seizing parts, and 

 consist only of two joints each, the second being a hook-shaped claw. 

 Tbc mandibles are enclosed in the proboscis formed by the paragnathi, 

 which are elongated and considerably thinucr at their extremities 

 than at their base. We have not the space to follow the author 

 through the details of tbo succeeding appendages, nor tlirough his 

 account of the chitinous carapace, which appears to be endowed with 

 a very fair degree of elasticity. 



Notwithstanding their parasitism the nervous system is very well 

 developed ; and it is possible to distinguish tbe supra- from the sub- 

 a3sophageal ganglionic mass. From the former there are given off 

 nerves for the antenmc and for tbe anterior portions of the head ; the 

 latter supplies tbe mouth organs and limb-;; but it is scarcely possible 

 to speak of a ventral ganglionic cord, and it seems to be more ap- 

 j»ropriate to give the name of ventral nerve cord to tlie two nerves 

 which pass backwards in the middle line fnnii tlic suIm esophageal 



