184 
BULLETIN OE THE UNITED STATES FISH COMMISSION. 
Family HES10NID£. 
HESIONE Sav. 
Hesione proctochona Schm. 
Ilesione proctochona Schmarda, Neue Wirbellose Thiere, 1861, p. 79, pi. 28, fig. 22G. 
Fallacia proctochona Webster, Annelids from Bermuda, Bull. U. S. F. C. 188-1, p. 311, pi. S, fig. 21. 
Hesione vittigera Ehlers, Annelids of the Blake, Stem. Mus. Comp. Zool., Cambridge, 1887, p. 143, pi. 41, figs. 1-4. 
Hesione prsetexta Ehlers, ibid, p. 147, pi. 41, figs. 5, 6. 
According to Schmarda’ s original description, the anterior portion of H. proctochona is character- 
ized by the absence of antennae, the presence of eight pairs of tentacular cirri, and four eyes. There 
are sixteen setigerous segments, and the anus is surrounded by a funnel-like expansion, whose edges 
are prolonged into ten conical projections. He also describes, but does not figure, two long anal cirri. 
Dorsal surface brown, each segment divided into ten bands by transverse white lines. Between every 
two of these lines is a broader white band. A small knob on either side, in front of each parapodium. 
Webster (loc. cit. ) describes from Bermuda specimens which he identities as this species. To 
Sehmarda’s description he adds the following points: There are two very minute antennae, so small 
as to escape detection with a hand lens; each parapodium bears on its outer, upper angle a slender, 
lip-like projection, and the ante-anal segment has no setae, but bears two very long cirri. 
Ehlers ( loc. cit. ) compares his new species, H. vittigera , with 11. proctochona. As between II. vittigera 
and II. proctochona ., as described by Schmarda, the agreements and differences are as follows: Both 
have 16 tentacular cirri and 4 eyes; neither has tentacles. (Note Webster’s discovery of tentacles in 
II . proctochona.) II. vittigera has 15 setigerous segments, H. proctochona has 16; the ante-anal segment- 
in the former has long cirri, while in the latter it is setigerous. (Note, again, Webster’s description 
of this segment in H. proctochona, which removes this distinction.) Ehlers’s pi. 41, fig. 1, shows 
unmistakably 16 bundles of setae, which leads to the suggestion that possibly there might have been 
an error in the description. It seems probable that the two may agree in this respect. H. vittigera 
has two unequal, lip-like projections on the dorsal surface of the parapodium, which are absent in 
II. proctochona. (Note, again, Webster’s description of one such lip in the latter.) There are no 
conical project ions surrounding the anal opening in II. vittigera, as described for II. proctochona. 
The Porto Rico collection contained a large number of specimens of this genus, which show so 
many resemblances to both the above species that it is very doubtful if the two are distinct. Number 
of setigerous segments, 16. There are eight pairs of tentacular cirri, four eyes, and two very rudi- 
mentary antennae, visible only on very careful examination. Dorsal surface marked with transverse 
brown lines, leaving a broader white band at anterior end of each segment. The outer angle of the 
parapodium bears two short lips. These may be nearly equal in size, or one may be very small and 
easily overlooked. The ante-anal segment bears no set®, but two long cirri. In favorable specimens 
the edge of the anal funnel is seen to be drawn out into conical processes, though the structures were 
lost in most of the specimens. 
The Porto Rico specimens agree with II. proctochona in the number of setigerous segments, in 
the possession of rudimentary antennae, and in having lobes on the anal funnel. They agree with II. 
vittigera in having two lobes to the dorsal parapodial lip, the smaller being frequently very small. In 
all other respects they agree with both species. Since, except in the first of the above-described 
features, the differences are points which might easily escape detection, I am convinced that the 
sjpecies are identical, and have included all of the Porto Rico specimens of Ilesione under the species II. 
■proctochona. 
Under the name H. prsetexta, Ehlers describes another species differing from II. vittigera, in having 
longitudinal instead of transverse brown marking, and in having but a single dorsal lip to the para- 
podium. Two specimens from Porto Rico show these longitudinal markings, but agree in the structure 
of their parapodia with II. vittigera. Elders suggests that the differences between II. vittigera and II. 
prsetexta are merely sexual. This suggestion is probably correct. 
Collected from Arroyo, Mayaguez, Hucares, Boqueron Bay, Playa de Ponce reef, Ensenada 
Honda (Culebra), Guanica Bay, Fajardo, Puerto Real, Porto Rico, Ponce, stations 6072, 6080, 6092, 
6096, 6098. 
The last specimen had fifteen setigerous segments and the markings of II. prsetexta. 
