104 



is a kind of articulation between the base of the posterodorsal rod and 

 the anterolateral rod, but it is not so distinctly seen as in Echinarachnius 

 excentricus. The anterolateral rods are strongly thorny in their outer part, 

 and also the preoral rods have a few thorns; they proceed at an obtuse 



Fig. '41. Skeleton of the larva of Encope micropora. A. from the ventral side; B. side view. 

 2^»/i. In figure A. the left posterodorsal rod is lacking. Letters as in fig. 20. vtr* the lower 

 ventral transverse rod. The asterisk has been omitted by a mistake in fig. B; it is the 

 outward directed rod in the right side of this figure which represents the lower transverse rod. 



angle from the dorsal arch. — The specimen from which the skeleton was 

 drawn, shows the peculiar anomaly of having only the left posterodorsal 

 arm developed, being otherwise quite normal. 



Mellita sexies-perforata (Leske). 



PI. IV, Fig. 2; PI. XIII, Figs. 5—6. 



A few specimens of this species containing ripe genital products were 

 obtained at Tobago, B. W. 1., on the 8th of April 1916 and fertilization 

 was made, which proved successful. The eggs^) are surrounded by a pig- 



1) W. I. Crozier, in his paper "On the pigmentation of a Clypeastroid Mellita sesquiper- 

 foratus Leske" (American Naturalist, Vol. LII, 1918, p. 554) states the egg of this species 

 to be "apparently larger than any other Echinoid egg that has been described", measuring 

 about 0.26 mm in diameter. From the present researches it is seen that much larger eggs 

 ca. 0.5 mm.) are found in several other Echinoids, Phyllacanthus parDispinus, Heliocidaris 

 erythrogramma, Peronella Lesueuri. Also Holopneustes purpurascens, Brisaster latifrons, Br. 

 fragilis, several deep-sea forms and the viviparous forms have large eggs. 



