NO.J123. PROCEEDINGS OF THE NATIONAL MUSEUM. 809 



In all cases the embryo was too rudiraeiitaiy to allow of even approxi- 

 mate ideutilieatiou. 



6. Cysts (Nos. 4838, 4822, U.S.N.M.) from stomach wall o£ the dogfish 

 {MusteJtis cani.s), collected at Woods IToll, ]\[assachusetts, July 22, 1S8G, 

 and July 22 and 25, 1887. In most cases these cysts are small with 

 rudimentary embryos, in which the proboscides are too rudimentary to 

 be of vahie in determining specific characters. A typical cyst measured 

 1.5 mm. in diameter and contained a blastocyst 1.04 mm. in length and 

 0.8 broad. 



In one lot embryos were obtained from blastocysts (alcoholic speci- 

 mens), which gave the following measurements : Length, 1.3 mm. ; diam- 

 eter, 1.1; diameter of proboscis, exclusive of hooks, 0.034; diameter, 

 including hooks, O.OG; length of hooks, 0.011) (Plate YI, figs. G, 7). 



These larvii' bear a strong resemblance to R. robustuni, Linton. 



7. Cysts from intestinal wall of common skate {Rata erinacea) {l^o. 

 5482, U.S.N.M.), Woods Holl, Massachusetts, August, 1884, twice. No 

 embryos. Cysts in first lot filled with amber-colored waxy secretions. 



The second find consisted of an elliptical cyst in the liver, 3i by 

 2i mm. in diameter, and about 1 thick; reddish brown. Contained 

 roundish granular masses from O.IG to 0.40 mm. in diameter. Cyst 

 had a pedicel which contained quantities of blood corpuscles of the 

 host. This may be a sporocyst. 



8. Small cysts from gill of goosefish [Lopliins piscatoriifs) {'No. 547G, 

 U.S.N.M.), Woods Holl, Massachusetts, July 18, 1885. 



These cysts were from 1 to 2 mm. in diameter, contained masses of 

 carbonate of lime, and could not be identified. 



9. Cysts from serous coat of intestine of billtish ( Tetraptitrus Imperator) 

 (No. 5501, U.S.N.M), Woods Holl^ Massachusetts, July 31, 1895. 



These cysts were filled with chocolate-colored waxy secretions. They 

 were evidently caused by the presence of a parasite which had under- 

 gone complete degeneration of tissue. 



10. Cysts from ])eritoueum of flounder {Pseudopleuronectes amerieanus) 

 (No. 5502, U.S.N.M.), Woods Holl, Massachusetts, August 23, 188G, and 

 August 10, 1887. These cysts are from 2 to 3 mm. in length and look 

 like tetrarhynchus cysts. Many of them are entirely or partly degen- 

 erate, containing much carbonate of lime, and in no case could the 

 exact nature of the cyst be made out. 



11. No. 4837. Cysts from peritoneum of butterfish {Stromateus tri- 

 acanthus), Woods Holl, Massachusetts, July 23 and August 24, 1887. 

 Small cysts less than 2 mm. in length, which contained an elongated 

 blastocyst (?) from 1 to 2.4 mm. in length. Some of these had an 

 aperture at larger end. The cysts had yellowish granular walls, and 

 inclosed the l)lastocyst (?), which was itself twisted in a transparent 

 membranous sac. The chyle of the intestine of the first lot was found 

 to contain numerous examples of these embryos — i. e., identical with 

 the blastocysts ( ?) above. 



