818 LAnVAL CESTODE PARASITES OF FISHES— LINTON. vol.xix. 



foregoing lots, either at time of collecting or in the subsequent exami- 

 nations of them incident to tlie "work of identification. These notes I 

 shall arrange under the head of the several hosts: 



1. Pomatomus saltafrix. — Cysts containing this parasite are of fre. 

 quent occurrence in this liost. They usual]}' occur in elongated cysts 

 lying on the viscera, in the mesentery, sometimes embedded in llie liver. 

 I find among my notes mention of one which had the exceptional i^osi- 

 tion of being under the submucous coat of the stomach. The length of 

 this blastocyst was 25 mm. It was rolled up irregularly into a round 

 mass. 



Usually these C3^sts can be readily recognized from those containing 

 Rhynchobothrium larva by their more slender habit, and, where the 

 outline of the contained blastocyst can be distinguished, by the neck- 

 like constriction near one end which separates the subglobose head 

 portion, in which the embryo lies, from the elongated body of the 

 blastocyst. The blastocyst is sometimes very long and does not seem 

 to bear any special relation to the size of the embrj'o, which, when fully 

 developed, does not exhibit much variation in size. The longest cyst 

 from the bluefish of which I have made measurements is 55 mm. ; ante- 

 rior part, 3 in diameter, elongating to G; posterior part, 1,1 in diameter. 

 After twenty-four hours in water one of these blastocysts measured 

 92 mm. in length. In one lot of cysts examined in alcohol, among the 

 usual elongated forms was one oval cyst, which contained a dark 

 brown mass of waxy consistency, in which a blastocyst of a synhotlirhim 

 was found. The posterior part of the blastocyst, instead of being 

 elongated, was contracted to 5 mm. in length, and was 2,25 mm. in 

 breadth. 



2. Gynoscion regalis. — I have not found this parasite of frequent 

 occurrence in the squeteague. When they do occur, they have the 

 same appearance as those of the bluefish. Dimensions of alcoholic 

 specimen: Length of blastocyst, 27 mm.; length of anterior portion, 

 6; diameter of anterior portion, 2.5; diameter of elongated j)osterior 

 portion, 2; length of embryo, apin^oximate, 4.G; breadth of head (com- 

 pressed), 0.48; diameter of neck, 0.17; length of contractile bulbs, 

 1.4; length of slender hooks on proboscis, 0.06 to 0.08. Color of head 

 portion yellowish brown, elsewhere whitish. 



3. tScomberomorns cavaJla, S. regalis, S. macnlatus. — This parasite 

 appears to be of frequent occurrence in these fish. I have not had 

 the ojiportunity of examining juany of these fish, but all that I have 

 examined have had a number of these parasites in elongated cysts on 

 the viscera. One specimen from JS. maculatus was found with a mass 

 of carbonate of lime in the posterior part of the blastocyst. 



4. PomolohuH niediocris. — A blastocyst, Mith everted embryo attached, 

 from the peritoneum of this fish, was very active when first removed 

 from the yellowish-white cyst, varying in length within short intervals 

 from 9 to 20 mm. The globular anterior portion from Avhich the head 



