662 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [22] 



ADDITIONS TO THE FAUNA OF VINEYARD SOUND — SURFACE DREDG- 



INGS. 



During the intervals between the Gulf Stream trips, shore collecting 

 and a large amount of surface dredging, both by day and night, were 

 done in the vicinity of Wood's Holl, by means of the two steam launches 

 belonging to the Fish Commission. In the surface dredging Mr. Emer- 

 ton took the most active part. The surface work was very productive 

 this season, not only affording a vast number of larval forms of Crusta- 

 cea, Echinodermata, Annelida, Mollusca, etc., but also a large number 

 of adult Annelida, belonging to the Syllidse and various other families, 

 including a number of very interesting new species. Certain species of 

 Autolytus were unusually abundant. Many thousands of specimens of 

 A. varians V. (formerly A. ornatus V.) were often taken in a single 

 evening, the males of both the red and green varieties being far more 

 numerous than the females, which were always bright red when con- 

 taining eggs. The males of a much larger species, the A. ornatus {Pro- 

 cercea ornataY., 1873, stem-form), were also abundant; the much larger 

 females, which are transversely banded with red, were taken in smaller 

 numbers. A small but very remarkable new species {A. mirabilis),* 

 first discovered by us in 1881, was not uncommon, but only the females 

 were taken at the surface. The stem-form occurred among hydroids 

 and ascidians at moderate depths. This species is remarkable for the 

 large number of sexual individuals that may be developing, simultane- 

 ously, from the stem-form. It is not uncommon to find it carrying five 

 or six sexual individuals, in various stages, one behind another. 



* Autolytus mirahilis V., Traus. Conn. Acarl., iv, pi. 13, figs. 8-10.— Stem-form long 

 and slender. Antennae, tentacular cirri, first pair dorsal cirri, and caudal cirri very- 

 long and slender, 4-6 times tlio breadth of the body ; median antenna and first dorsat 

 cirrus longest; second dorsal cirri twice the breadth of body ; others varying in 

 length, but mostly longer than breadth of body ; two long, narrow epaulets, extend- 

 ing from the head back to third body-segment. Stomach large, oblong ; pharynx 

 slender, with one flexure, denticulate at the end. The most anterior formation of the 

 sexual young takes place behind the fiftieth segment ; in one individual (see Fig. 8, 

 loc. cit.) six female individuals follow one another, the largest one b«ing nearly ready 

 to separate, and having 22 segments, with a well developed head, four eyes, and 

 long antennae. Some detached females, bearing eggs, have, however, no more than 

 16 to 20 segments. 



Vineyard Sound and oflf Gay Head, 4 to 8 fathoms, among hydroids, 1881 and 1882. 



Female: Small, with only one pair of slender cirri, longer than breadth of head, on 

 the buccal segment ; two anterior body-segments with only short setae ; capillary 

 setae begin on the third segment ; two pairs of eyes close together, the anterior 

 larger ; three antennae nearly equal, long and slender, three or four times the breadth 

 of the head ; caudal cirri, when fully developed, about as long as the antennae ; dor- 

 sal cirri slender, longer than breadth of body. Length 3™°» to S.S""". Color, when 

 containing eggs, dark olive-brown; after eggs are laid, pale greenish; eyes dark 

 brown. Wood's Holl, surface, evening, August 2 to September 18, 1882; off Gay 

 Head, with the stem-form, 1881. Description from life. 



