492 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [40] 
condition along with some more usual host which had been eaten by the 
shark a short time before the latter was examined. However interest- 
ing this supposition may be, it is hardly necessary, as there is no rea- 
son why (@. obscurus should not be a proper host of &. agilis. 
Echinorhynchus acus Rudolphi. 
[Plate V, Figs. 7-13. ] 
Rudolphi, Wiedmann’s Archiv., ii, 2,51; Entoz. Hist., 11,279; Synops., 71 and 324. 
Zeder, Naturg.,150. Westrumb, Acanthoceph., 24, Siebold, in Burdach’s Physiol., 2, 
Aufl., ii, 196(ovula). Drummond, Charlsworth’s Mag. of Nat. Hist., ii, 516. Belling- 
ham, in Annals of Nat. Hist., xiii, 256. Dujardin, Hist. Nat. des Helminth., 540. 
Creplin, Nov. Obs., 43, and in Ersch. and Grub. Encyclop., xxxii, 284. Leidy, in 
Proceed. Acad. Phila., viii, 48. Van Beneden, Mem. Vers. Intest., 279-287 (develop- 
ment). 
For detailed synonymy and habitats, see Diesing, Syst. Helm., ii, 39-40, and Revis, 
d. Rhyngodeen, 747. 
Proboscis linear with about twenty series of hooks; neck none; body 
long, greatest width a short distance back of proboscis, subattenuate 
posteriorly, bluntly rounded at posterior end. Length 27 to 81™™ (Du- 
jardin), breadth 2"™; males half as long as females ; color usually white. 
“The color is very various but generally white when distended, 
though frequently accompanied at the same time by a tinge of orange, 
pink, or cinereous. Sometimes the whole animal is reddish orange 
(especially the male), and sometimes the whole is ivory white with a 
solitary minute crimson dot here and there” (Drummond), 
Some specimens flat, thin, with regular outline, others cylindrical with 
irregular transverse rug. All the specimens noted by me were white 
or faintly tinged with yellow. 
The following measurements were made on alcoholic specimens: 


Dimensions. No.1, 9 | No.2, ? | No. 3,0 
mm. mm. mm, 
Length of specimen ...--- ------------ +--+ --0e eee cere eter ee eee e eee 46. 00 45. 00 20.00 
Length of proboscis ..---..--------+---+++eereee eee ener renee eee nee n ee 1. 04 1.06 0.96 
Breadth of proboscis ..--------------00---+ eee eee reece eee renee Bocc eee 0. 28 0. 32 | 0. 28 
Length of proboscis sheath ..-...---------++-+0+----++ ese eee cree ee eee ee: 1.44 1. 60 1.40 
Breadth of proboscis sheath. .-....------- 22-0. ee eee eee e ener eee e ee eee: 0.3 0. 36 | 0. 36 
Breadth of body, anterior. ..-..------------ 2200-2222 e renee eee eee eee 0.75 0, 80 0. €0 
Breadth of body, antero-median...-...-.--------------+++-+e+e-eee eee eee 2.00 | 1. 60.) 1.20 
Breadth of body, near posterior end ....-..----------+-----+ sees eee eee: 0. 60 | 1.10 0. €0 


Length of longest living specimen, 60™™, 



Dimensions. Millimeters. | Millimeters. | Millimeters. 
| 
Longest diameter of ovarian masses. .-.----++-+++-+--++-++ 0.11 0. 07 0. 08 
Shortest diameter of ovarian masses ......----+---+--++---- 0.075 0.05 0. 07 
Length of 0va..---.------ +--+ 2+ seen eee eee eee e eee ee eee 0,13 0.114 0.112 
Breadth of OVA ....--0------ ce ceen ce = etn n nn enn seeenncaerase 0. 03 0. 055 0. 023 
Length of embry0....-----+-- +--+ 2+ ++ eee eee e nee ee eee ees 0. 098 0. 08 0, 076 
Breadth of embryo .....---- eee n eee eeee eee e nescence weenene 0, 017 0.018 0. 015 
eee 
|, nt 
ee ean — 
ff 
J 
+ 
