402 Baldwin Spencer : 



margin is bounded by a very distinct band of tinely punctated 

 material that stands out clearly as a light band when the 

 organism is viewed against a dark background. For the pur- 

 pose of convenience in reference, I have numbered the lateral 

 margins of the quadrangular mass, 1, 2, 3 and 4. 



In Figure 1 is seen a general view of the organism. It is 

 quite transparent, and by careful focussing under a low power 

 the whole of the structure of the body can be seen. Figure 1 

 represents a side view, Figure 3 a view of the oral surface, and 

 Figure 4 a diagrammatic transverse section. The dimensions 

 of the largest specimen are as follows, but there is very little 

 variation in size amongst them. Distance between oral and 

 aboral surfaces, 11 mm. ; width between margins 1 and 3, 

 d mm. ; downward projection of margin 1, 2.5 mm. 



General Form. — When the animal is alive the body is prob- 

 ably a fairly regular, quadrangular shaped mass of stiflf jelly. 

 The mouth lies in the middle of the oral surface, and leads mto 

 a simple, wide, flask-shaped cavity occupying the centre of the 

 jelly mass. From the central point of its distal end there arises 

 a very small but distinct tube which runs up to, and opens 

 on a conical projection on the aboral surface. (Fig. 2.) 



The margin numbered 1 (Figs. 1 and ')) is prolonged beyond 

 the oral surface so as to form a conical projection, the three 

 sharply marked edges of which are serrated. The surface that 

 lies between the margins 1 and 2 (Figs. 1, 2, 4 and 5) is in- 

 dented by a deep groove which penetrates the jelly almost as 

 far as, but not quite to, the central tubular cavity. On the 

 aboral surface the jelly is lifted up (Fig. 2) to form a conical 

 projection, which is cut through by the groove, into which, at its 

 upper end, the small tube from the central cavity opens. The 

 groove, which forms one of the most remarkable features of 

 the organism, is a very definite structure, and extends to within 

 a short distance of the oral surface. Except at the aboral end 

 its lips are close together. At the oral end one lip is continued 

 (Fig. 5) as a well-defined line of densely punctated material, 

 precisely similar to that of the margins, marked with ten or 

 eleven serrations. It passes down, curving gracefully on to the 

 aboral projection already described, the groove not extending 

 so far as its termination. 



