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Telepsavus (?). 
Plates III. and VIII. 
The most common mesotrochal larva at Newport is similar to one supposed 
by Claparéde and Metschnikoff* to be the young of Telepsavus. The adult 
Telepsavus has not been found in Narragansett Bay, and the allied genus 
Spiochetopterus, to which Dr. E. B. Wilson ¢ doubtfully refers larve from the 
Chesapeake Bay with many points of resemblance to those which are about to 
be described, has also not yet been recorded from the locality where my studies 
were made. 
A very common worm larva, which has the whole surface ciliated and an 
apical compound flagellum, but in which no equatorial ring of cilia had formed, 
is very commonly found at Newport in our dip-nets. These larve (Pl. VIII. 
Figs. 12, 13, 14) resemble closely the young of Chetopterus, but are larger, and 
in older stages more elongated. They resemble closely the young Telepsavus 
figured by Claparéde and Metschnikoff, and on that account are here referred 
to this genus, although they have not been raised into any member of the 
present series. They might equally well, however, be connected with the 
larve which have been identified as belonging to the closely allied genus 
Phyllochetopterus. 
The young Telepsavus (Pl. III. Figs. 6, 7) is quite large as compared with 
other Annelid larve, and can with the unaided eye be easily distinguished swim- 
ming about in the water. The body is swollen into an almost globular shape, 
and is divided into two regions by a mesial ring of cilia. In the youngest stages 
of growth neither of these divisions is segmented. A fleshy triangular lobe, 
rounded in front, is largely developed, and extends beyond the mouth on the 
dorsal side of the head. The lower lip is bilobed. There are two cephalic 
eye-spots in the youngest larva. The whole body is covered with cilia, and a 
prominent median cilium is found on the preoral lobe near its rim. The 
mouth (m) has a triangular shape, opening below the lobe, and is surrounded 
by fleshy lips. No tentacles or cephalic appendages are yet developed. 
The posterior portion of the body is short, tapering to the posterior pole of 
the larva, which bears a segmented (?) tail (Fig. 7, a). The anus is dorsal in 
larvee of this age. 
Almost the whole interior of both cephalic and caudal regions of the body 
is taken up by a large cavity (s) called a stomach, which occupies the greater 
part of the anterior body region, and extends a short distance into the posterior 
part. Its walls have a green color, while those of the body are brown and 
pink, A diverticulum from the stomach extends forward in the ventral region 
of the body cavity below the esophagus. The cesophagus in its course bends 
twice upon itself, and opens into the stomach on the dorsal side. Its walls are 
* Zeit. Wiss. Zool., XIX., 1869. 
t Observations on the Early Developmental Stages of some Polychxtous An- 
nelides, Stud. f. Biol. Lab. Johns Hopkins Univ., Vol. II. No. 2. 
VOL. XI.— No. 9. 12 
