NO. 1123. PEOCEEDIXGS OF THE NATIONAL MUSEVM. 801 



small opaque mass near the surface of tlie blastocyst. lu the walls of 

 the latter were two siuuons vessels which started from the Aicinity 

 of the embryo and ran in o})posite directions around the periphery of 

 the blastocyst. ISo. 6 from Bothns macidatus. In this the longest 

 hooks, however, are 0.04 mm. in length. Other dimensions of an 

 embryo (alcoholic) are: Length, G mm. ; breadth of head, 0.94: ; length 

 to base of contractile bulbs, 4; diameter of neck, 0.47; length of bulbs, 

 1; diameter of proboscis, exclusive of hooks, 0.08. Xo. 7 from the 

 tautog. The arrangement and character of the hooks in this also 

 agree exactly with that of the foregoing; the length of the large stout 

 hooks is 0.05 mm. Otber dimensions practically the same as in Xo. G. 

 No. 5 from the mackerel. The cysts in this lot are of great diversity 

 of shape. Two embryos were examined, and although the [troboscides 

 were retracted the characteristic irregular hooks of R. impurisphie 

 could be seen. The length of the longest hooks seen was 0.04 mm. in 

 one and O.Oof), near base of proboscis, in the other. Xo. 9 from sea 

 bass. Cj'sts pyriform, blastocysts with embryo situated at one end; 

 proboscides retracted, but hooks correspontl with R. imparispine. 



^os. 10, 10, 17, and 18 from the cod and Kos. 12 and 13 from the 

 haddock. The cysts are pyriform and in many instances pediceled; 

 in No. 10 there was a cluster of pyriform cysts. When embryos were 

 liberated, the arrangement and character of the hooks proved to 

 be identical with those figured from other hosts and referred to R. 

 imparispine. 



10. RHYNCHOBOTHRIUM SPECIOSUM, new species. 

 (Plates TV, rigs. 13-14; V, ri<;8. 1-7.) 

 Rhynchohoihrium, sp.. Lintox, Amer. Nat., XXI, p. 195, Feb. 1887, pi. X, rigs. 1-6. 



I venture to give a new specific name to a Rhyncliohothrimn which I 

 hav'e found very commonly infesting the bluefish and not infrequently 

 in a variety of other fish. Although only the larval form is known to 

 me at present, the characters of the bothria, and j)articularly of the 

 proboscides, are so well defined that one can hardly fail to identify it 

 when specimens in good condition and suflhciently developed are met. 



Following is a list of the finds of this parasite which I have recorded 

 in my notes. All except ISTos. 9, 10, and 11 were collected at Woods 

 Holl, Massachusetts. Where not otherwise stated, it will be under- 

 stood that the specimens were found on the serous covering of the 

 viscera or mesentery. 



Proc. ]Sr. M. vol. xix 51 



