174 ILLINOIS BIOLOGICAL MONOGRAPHS [174 



PROTEOCEPHALUS SALVELINI (Linton) 

 [Figs. 143, 144] 

 1897: Taenia salvelini Linton 1897:424 



1911 : Proteocephalus salvelini La Rue 1911 :475 



Linton (1897:424) described this species. La Rue (1911:475) in- 

 cluded this form in a list of species of Proteocephalus. 

 Linton's description reads: 



"TAENIA SALVELINI. Type.— No. 481 1, U. S. N. M. From intestine of 

 Great Lake trout (Cristivomer namaycush) ; Outer Island, Lake Superior; J. W. 

 Milner. In this lot are several small Taeniae; scolices with few roundish or 

 oblong segments, in some of which the male genitalia were developed, otherwise 

 immature; length from 3 to 5 mm. 



"These specimens bear some resemblance to the young of T. torulosa, Batsch, 

 as described by Zschokke (1884). 



"Head usually rounded in front, with suckers directed anteriorly. The diam- 

 eter of the head varies according to state of contraction, usually 0.3 to 0.4 mm. ; 

 suckers relatively large, usually directed forward, prominent, rather deep. 0.15 to 

 0.18 mm. in diameter, aperture 0.1 mm. in diameter. Neck assuming various con- 

 traction shapes; in some continuous with head and merging imperceptibly in body; 

 in others separated by a constriction behind the head ; in others not separated 

 from head by constriction but with segments beginning abruptly ; numerous cal- 

 careous bodies in neck behind head. Usually first segments indistinct, broader 

 than long. Oldest segments longer than broad ; genital aperture near middle of 

 lateral margin a little nearer anterior margin. Vitellaria making a narrow border 

 along lateral margins ; beginning of germ gland at posterior end ; central region 

 in front of rudimentary germ gland occupied by prominent testicular lobes ; cirrus- 

 bulb oblong, elliptical, convex on posterior, straight or slightly concave on anterior 

 surface; cirrus enters from inner anterior edge of bulb, then traverses middle of 

 bulb to orifice; length of bulb, 0.26 mm.; diameter, 0.14 mm.; largest segments, 

 1.5 mm. in length and 0.75 mm. in breadth." 



Linton's figures of the head are reproduced (Figs. 143, 144). 



Since this description is insufficient for determination in compari- 

 son with the forms described here Dr. H. B. Ward very kindly secured 

 Linton's specimens from the National Museum at Washington. Unfor- 

 tunately but fragments remained. These fragments were cleared and 

 examined in glycerine. The writer's observations on the heads agree 

 very well with Linton's records. A fifth sucker or a trace of one could 

 not be found. The suckers in their maximum diameter measure 0.17O 

 mm. the sucker opening about 0.100 mm. The head is flattened dorso- 

 ventrally. In general shape it resembles some dilated heads of P. pin- 

 guis but is larger. Linton says that it resembles young specimens of 

 P. torulosus, however its measurements are quite different. It must be 

 left for the present in the list of inadequately described species. 



