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Five specimens in all were taken; some of them were attached to cylindrical stems of 

 a coralline organism most probably. The length of the capitulum of the largest specimen taken 

 by the "Siboga" is 6,6 mm., that of its peduncle is about i,6 mm. A young specimen is 

 attached to the peduncle near its e.vtremity. 



The "Siboga" took these specimens at three different Stations: 



Stat. JT- June lo, 1899. Lat. 3°27'S., Long. 117° 36' E. Depth 59 m. Bottom: fine grey 



coral-sand, i specimen. 

 Stat. 80. June 13, 1899. Borneo Bank. Depth 50 — 40 m. Bottom: fine coral-sand, i specimen. 

 Stat. 289. January 20, 1900. Lat. 9°o'.3 S., Long. 126° 24.5 E. Depth 112 m. Bottom: mud, 



sand and shells. 3 specimens. 



Formae dubiae. Though I have long been in doubt on the matter, I consider a 

 few specimens (two large, two smaller and a few very small specimens) as belonging also to 

 this species, which were collected by H. M. S. "Siboga" at Station 318 at a depth of 88 m., 

 as also two small specimens taken at Station 294. Their shape is slightly different, being much 

 flatter and the peduncle is shorter. The largest specimen has a capitulum over 7 mm. long 

 and may be considered a full-grown specimen as it is furnished with well-developed egg-sacks. 

 This animal is figured on PI. II, fig. 18. In this specimen the proportion of the t\vo segments 

 of the scutum is different from what it is in the individual represented in fig. 14 of the same 

 plate. Other differences are shown by the figures and are perhaps not important enough for 

 minute description. Of one of the specimens of Station 318 I have prepared the valves and 

 made with their aid the drawing fig. i, PI. III. I have made a drawing further of the smallest 

 specimen of all (PI. Ill, fig. i A), taken also at Station 318 and of one of the slightly larger 

 ones (PI. Ill, fig. 1 B) of Station 294. In that of Station 318 the shape of the shells is still 

 quite different from that in the full-grown and those of Station 294, having a capitulum of 

 1,8 mm. in length, may be considered as forming the transition between the very small one 

 with a capitulum of 1,25 mm. and the full-grown form. 



The position of the stations where these forms were taken was as follows: 



Stat. 294. January 23, 1900. Lat. 10° 12'. 2 S., Long. 124° 27'. 3 E. Depth -j^, m- Bottom: soft 



mud with very fine sand. Two small specimens. 

 Stat. 318. February 22, 1900. Lat. 6°36'.5S., Long. ii4°S5'.5E. Depth 88 m. Bottom: fine 



yellowish grey mud. Several large and smaller specimens. 



4. Dichelaspis Weberi n. sp. PI. Ill, fig. 2 — 7. 



Capitulum much compressed with the ape.\ slightly produced. Scuta with the basal segment 

 narrower than the occludent segment and not quite half as long. Terga with three unequal 

 maro-in'al projections on the scutal margin of the valve. Carina much bowed, internally very 

 concave, terminating downwards in a small spatula-like disc. 



General appearance. Capitulum compressed, flat. Valves relatively small, narrow, a 

 laro-e interspace between the carina and the other valves. Valves covered by a thin transparent 

 membrane only. Peduncle cylindrical, much shorter than the capitulum (PI. Ill, fig. 2). 



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