132 PEOCEEDINGS OF THE NATIONAL MUSEUM vol. 83 



greater part of the neck, becoming thrown into coils just anterior 

 to the bulbs. The spines on the proboscides, as far as observable 

 in the everted part, are arranged in two groups of five each. Near 

 the base of the proboscis one set of five spines in each whorl con- 

 sists of recurved clawlike spines, tending to become straight and 

 elongate, at first one or two in a set, in more distal whorls all of 

 them. Manj^ of the spines near the base have more or less well- 

 developed prongs (pi. 8, fig. 4), After the first six or eight whorls 

 all the spines tend to become elongate, only slightly curved, and to 

 have their prongs flattened out (pi. 8, fig. 3). Near the base these 

 elongate spines are about 50|U, to GO/x long, but they gradually grow 

 larger until they reach a length of about llOfi. At about 900/a from 

 the base the spines in one series of five change rather suddenly, in 

 the space of two or three whorls, to very stout, strongly curved, 

 clawlike spines with stout bases, the spines in the other series re- 

 maining broad, flat, elongate, and slightly sinuous (pi. 8, fig. 2). 

 Examination of tlie inverted part of the proboscis shows that at 

 least some clawlike spines continue nearly to the tip, but the form 

 and arrangement of the spines in this part of the proboscis could 

 not be made out clearly. 



Following are the characters that I think should be possessed by 

 a specimen before it can be correctly assigned to this species : Larvae 

 with " blastocyst " divided into an anterior oval or spherical vesicle 

 containing the head (unless pressed out) and an elongate, posterior 

 tail-like portion. Head when pressed out of vesicle remains attached 

 to it unless broken. Bothria four, spreading out anteriorly and 

 each with a sucking disk directed forward. Head and neck 3 or 

 more mm in length, and about 200jli broad in narrowest region; 

 contractile bulbs about 1 nun or more in length and about one- 

 tenth to one-eighth as wide as long. Proboscis sheaths nearly 

 straight in anterior half or two-thirds of length of neck, but thrown 

 into coils just anterior to bulbs. Retractile muscles of proboscides 

 attached near anterior end of bulbs. Proboscides about 3 mm in 

 length. Spines on proboscides arranged in two groups of five. On 

 basal portion of proboscides, except first six or eight rows, spines 

 slightly curved and bladelike, frequently notched at tip, and reach- 

 ing maximum length of about llO/x. About 1 mm from base, spines 

 in one set of five change to a stout clawlike form, wliich is main- 

 tained in at least one set of spines to tips of proboscides. 



GYMNORHYNCHUS MALLEUS (Linton, 1924) 

 Plate 8, Figuiies 5, G 



The larvae of this species were described and figured by Linton 

 (1897) as Tetra7'hynchus erinaceus. These larvae were transferred 

 by Linton in 1905 to the genus Synhothrium^ and in 1924 were as- 



