438 BULLETIN OF THE UNITED STATES FISH COMMISSION. 



PROTOZOA. 



8. Sporozon. [PI. i, figs. 1-:?.] July L'fi ami 27, 1899. 



About half the fish exaiiiined on these tlates were found by Mr. .1. A. Siewart.-^on to be infested 

 with a |)ara.«ite among the muscles of the back and side. The,se were not examined closely at the time 

 of collection, but piei'e,s of mui^cle with cy.-*ti< were jjreserveil and subsequently sectioned. They were 

 then seen to be sporocyst.s. On July 9, 1900, a young herring 8 <-m. in length w:is examined. The 

 flesh along the back and sides, from head to tail, was filled with small white tumors. While these 

 were of various sizes, none were large. Two of the larger cysts me;U'JUred 1.74 by 1. Hi ami I.Uiby 

 0.5S nun. in the two principal diametei's. The s|)orozoa when placed si> that the four jmlar vesiclre 

 are U])permost are s()i'arish in outline with rounded conu'i-s, and measure abi>ut 0.(H»7 nnii. in iliameter 

 (fig. 3). The |)olar vesicles are of a faint griH-nish tint, the remainder of tin- spore colorle.-'s. 



Sections of the infested nni.scular ti.-<s>ie show that the spores lie iii clusters, which are in some 

 cases enveloped in a definite connective cyst and in others not. The spores were also seen in great 

 nundDers lying along the intermuscular connective tissue fascia. One instance wiLs noteil in a series 

 of cro.ss sections wliere a clustiT of spores had established themselves in tlie midst of a muscle fiber 

 (fig. 2). I am informe<l by Mr. E. K. Tyzzer, who is studying this and otiier myxos|Miridia, that he 

 has not found the herring infested with this form, but that about half the young alewivcs examined 

 arc infested; further, that the s]><irocy.sts are not common in the larger fish, and, nmreover, the spore.s 

 are not in such good londition. The vitality of the infested fish must nece.-^sjirily \>e much impaired 

 liy the presence of sporozoa in such great abundance in the tissues, whereby they fall victims to 

 their enemies in larger proportional numbers than d<i their healthy a.>j.sociati-s. It is for this rea.son, 

 doubtless, that there is a less proportional number <<i infested individuals among the larger lish than 

 among the smaller. 



Clupanodon pseudohispanicus, Sjiniiiih Siirdine. 



FOOD. 



Two small sjiecimens were examined .Viiirust l.i, l.S9it. The alimentary tract contained numerous 

 cope]>ods. 



TKEMATODBS. 



1. Dislumum ap/ieii(licul(ilmii Hudolphi. Few. Dimensions of one in glycerine, in millimeters: Length, 

 0.86; diameter of oral sucker O.Oli, of ventral sni'ker 0. 12. 



Fomolobus mediocris, Hickurij Shml. 



FOOD. 



July 28, 1899; 1; stomach empty. August 13, UtOO; 1; fish scale and jien of s<iuiil in pylorus. 

 August Hi, 1900; 1; fragments of Crustacea and a small crab in alimentary tract. 



XE5r.\TOI)ES. 



1. -l.smri'.i sp. [PI. V, figs. 41— lo.] 



Twenty-eight large and 3 small specimens from stomach, July 2S, 1,S99. Ivcngth of a male .SO 

 mm., of a female 44 nun.; length of smaller specimens, 10 nun. Four |jostanal papillic and 28 jjreanal 

 on each side in male; of the preanal the 10 posterior are the smaller, the remaining 18 larger and in set.s 

 of 2; both kinds are in a single row. The.se siK'cimens have many points of resemblance to A. dnralti. 



CESTODES. 



2. lAtnnl cfsliiilcs {Scoter jtdliitiiorjjhiis Dujanlin). Free in intestine, July 28, ISiHt, and Aug. 13, 1900. 



For account of similar forms, see 4, pp. 789-792. 



TUKM.MIU )!■>;. 



3. DiMomum appemliciilatum Rudolphi. Stomach and pylorus. See 7, p. 289, pi. xxxvi, figs. 2.5, 20. 



July 28, 1899; 33. Aug. 13, 1900; numerous. Aug. 10, 1900; numerous. 

 Dimensions in millimeters, life: Length. 2; diameter of oral sucker, 0.09; diameter of .Hcetabulum, 

 0.18; ova, 0.024 and 0.012 in the two principal diameters. 



