NOTES ON AMPHITRETUS. 



87 



manifested in sluggish movements of the arms and other parts. It was 

 soft, transparent and, as already mentioned, almost jelly-fish-like both 

 in consistency and general appearance. The outline of the entire 

 animal was like that of an elongate bell, rounded at the blind end and 

 the edge of which ran out into the short free ends of the arms. The 

 appearance was strikingly similar to that of Alloposus mollis, as 

 figured by Verrill (Bull. Mus. Comp. Zool., VIII ; Trans. Conn. 

 Acad., V) and especially of a new species of the same genus {A. pacificus 

 Ij.*), known to us from the Sagami Sea. 



The specimen was considerably compressed nearly but not quite 

 dorso-ventrally ; the eyes were turned somewhat to the right and the 

 siphon to the left. This compression was however evidently due to the 

 fact that the animal had lain overnight and suffered to become morbid in 

 the position indicated in a flat vessel containing too little sea-water for 

 the soft body to have retained its natural, probably cylindrical form. In 

 this conditio'i the total length measured 190 mm., and the breadth at the 

 middle, approximately 70 mm. 



A thick layer of a delicate, colorless and perfectly transparent 

 gelatinous tissue covered up alike the body, the head and the umbrella 

 continuously, exactly as in Alloposus. So far as the external outline was 

 concerned, the layer exhibited no constriction or demarkation between 

 any of the three parts just mentioned. It was over 20 mm. thick at the 

 posterior end and 8 — 10 mm. at the sides ; but it must be borne in mind 



* AUoposic* paciftcua Ij. N. sp. Two specimens have hitherto been obtained in the 

 Sagauii Sea and are preserved in the Sci. Coll. Museum. One is small, measuring only 

 about 54 mm. in total length; the other is about 1 IG mm. long. Both without a 

 hectocotylized arm. They closely resemble A. mollis Verrill, except in the fact 

 that the suckers are arranged in a single row for the greater part of the arm-length, 

 being biserially arranged only in the free tip. The body is unusually compressed 

 antero-posteriorly, its length (as measured from the posterior end to the mantle-edge) 

 being about £ of the total length. There are two buttons at the siphon base, fitting into 

 grooves on the inner side of the mantle. It is apparently either this arrangement or the 

 depressor infundiboli that was called by Verrill " the lateral longitudinal commissures," 

 while his " median-ventral commissure " seems to be simply a part of the ventro-median 

 septum, which, in this genus, is brought so far forwards that its anterior e Ige is partially 

 visible from the outside in the middle of the mantle-opening. — Ijima. 



