m 



ENTOZOA OF MARINE FISHES OF NEW ENGLAND. 



459 



to be much narrower than the first joint, with curved regular outlines, 

 except at the posterior edge, where there is a shallow notch. The front 

 of the head is bluntly conical, expanding quickly, then moderately con- 

 tracted, making a kind of knob or button at the apex 5 this knob is 

 nearly circular. Measuremen ts showed that the lateral diameter was but 

 little greater than the marginal. In the larger specimens this convexity 

 of the bothria had entirely disappeared, the thin membrane having col- 

 lapsed and the typical fossae of the Dibothrkv make their appearance. In 

 the larger specimens, also, the bothria are much shorter in proportion to 

 their width than in the smaller specimens (Fig. 7). The first segments 

 are distinct, length as great or even greater than the width, triangular. 

 The median and posterior segments are much crowded, width as much 

 as or even more than ten times the length, alternately long and short, 

 sometimes roughened by transverse wrinkles toward the posterior end. 

 Posterior end bluntly rounded (Fig. 8). 

 The following measurements are from alcoholic specimens : 



Dimensions. 



Length of strobilG 



Length of head 



Diameter of head, lateral apex 



Diameter of head, marginal apex 



Breadth of hothrium , widest part 



Greatest marginal diameter of head 



Lateral diameter of first segment 



Marginal diameter of first segment 



Length of first segment 



Greatest width of strobile 



Average length of segments near posterior 



Length of posterior segment 



Breadth of posterior segment 



No. 1. 



mm. 



55.00 

 0.00 

 0.34 

 0.30 

 0.42 

 0.46 

 0. 58 

 0.34 

 0. 34 



2. 50 

 0.17 

 0.20 

 1.40 



No. 2. 



hi in. 

 07. 00 



0.25 

 0.25 

 0.40 



0.70 

 0.40 



1.00 



No. 3. 



111 111. 



94. 00 

 0.64 

 0.33 

 0.33 

 0.52 



0.60 



0.40 

 1.80 

 0.15 



No. 4. 



0.04 

 0.34 

 0.34 

 0.54 



0.68 



It will be seen upon comparing Figs. 6 and 7 that there is great va- 

 riety of form to be found in the bothria of these worms. Other forms 

 could be given, but it is believed that those chosen for illustration are 

 sufficiently typical to prevent mistakes in identification. In many 

 specimens the convex outline of the bothria is lost, while the other pro- 

 portions of Figs. 5 and 6 are preserved. In cases where care is not 

 taken the preserving fluid may distort the bothria. 



I did not observe any indication of the hooks on the head, mentioned 

 by Wagener for D. microcepltalum (Entwickelung der Cestoden, p. G9, 

 tab. vii, figs. 77 and 77a). The resemblance of this worm to Wage- 

 ner's figure is sufficiently close to indicate a probable identity. The 

 close relationship of the hosts, Orthagoriscus mola and Alutcra Schcepfti, 

 does not lessen this probability. 



In the absence of positive proof of such identity, which can be ob- 

 tained ouly by observing some other stages of development, I think it 

 best to classify this worm as a new species with the provisional name 

 D. aluterce. 



