6 THE VOYAGE OF H.M.S. CHALLENGER. 



1. Sternaspis princeps, n. sp. (PI. I. fig. 1). 



Alono- the middle of the ventral surface there runs a shallow furrow, and each half i.s 

 divided by a diagonal keel into an anterior larger and a posterior smaller triangle. 

 There are forty tufts of setae on the margin of the shield. The whole body is studded 

 witli fine scattered chitinous setae, each having at its base a number of smaller chitinous 

 pieces grouped together into a small wart-like protuberance. 



Of the two specimens preserved the larger is represented in fig. 1. 



HaUtat— Station 169, July 10, 1874; lat. 37° 34' S., long. 179° 22' E. ; depth, 

 700 fathoms ; bottom temperature, 40° "0 ; blue mud ; trawled. 



Genus 2. Echiurus, Guerin. 



The proboscis has a deep furrow, but is not sjalit in front. There are two anterior 

 ventral hooked setae, and one or two circles of posterior bristles. Two pairs of segmental 

 organs, two internal anal vesicles (Analkiemen) with ciliated funnels. 



2. Echiurus unicinctus, von Drasche (PI. I. fig. 2; PI. III. figs. 11, 12). 



Echiunig unicincfus, von Drasche, Ueber eine neue Echiurus-ATt aus Japan, &c., Verliandl. 

 d. k. k. zool.-'bot. Gesellscb. Witii, BJ. xxx. pp. 621-628, Taf. xxx. fig. 1, Jahrg. 

 1880, 1881. 



Short proboscis. There is only one circle of j)Osterior bristles. The paired 

 appendages of the segmental organs are long and spirally coiled. 



Out of twenty-one specimens the average length was 7 cm. and the breadth about 

 15 mm. The largest was 9|- cm. lojig. All were much contracted. The grooved 

 proboscis is not very sharj^ly distinguished from the body, it has a conical form and is 

 very short, not exceeding 6 mm. in its contracted state. The papillae on the skin 

 measure from 0'2 to 0"5 mm., and look like numerous little knots. They are not 

 arranged in transverse rows except at special places, as for example close beside the 

 ventral setai. The preserved specimens are of a bright yellowish- brown colour. 

 Immediately behind the base of the proboscis on either side of the median ventral line 

 are the two moderately strong hooked setae. At the posterior end of the body there is an 

 anal region bordered by a single circle of golden stylet-like setae, bent slightlj' outwards. 

 In most of the specimens there were eleven of these setae, but in some nine, ten, twelve. 

 or thirteen. As in the other species of Echiurus, the circle of setae exhibited a distinct 

 gap on the ventral surface. Here and there reserve setae may be seen. In regard to the 

 musculature, it may be noted that the internal layer of circular muscles consists of nl)out 



