62 Mr. H. N. Moseley on the [Nov. 25, 



The deep blue colouring of the corallum of Heliojpora is due to an 

 amorphous colouring-matter insoluble in strong hydrochloric acid, but 

 soluble in acidified alcohol. It forms an intensely blue solution of a sul- 

 phate of copper colour, which transmits the blue and part of the green 

 only of the spectrum. 



In the soft tissues of Heliojpora an ectoderm, entoderm, and mesoderm 

 are to be distinguished. The ectoderm is composed of club-shaped cells ; 

 it has the usual disposition. Small oval nematocysts are present in it 

 and in the upper part of the mesodermic layer beneath. The mesoderm 

 consists of three histological elements, homogeneous connective tissue, 

 layers of connective-tissue cells, and finely fibrous calciferous tissue. 

 Prolongations of the two former form sacs liniug the coenenchymal tubes 

 and calicles. The sacs are further lined by the entoderm, which consists 

 of spherical cells containing yellow pigment, as in other Alcyonarians. 

 Only a surface-layer in Heliojpora is living. Hardly any soft tissue is to 

 be found in the tubes beneath the last-formed tabula. The sacs lining 

 the tubes do not communicate anywhere directly with the exterior, but 

 are connected with one another above, and with the calicular cavities, 

 by wide transverse canals. The superficial tissues are permeated by 

 smaller canals. The polyps of Heliojpora have eight mesenteries and 

 eight lobed tentacles. In the contracted state of the polyp the tentacles 

 are completely introverted, and rest in the inter-mesenterial spaces. 

 The stomach is like that of any other Alcyonarian. Retractor muscles are 

 present, which are disposed with regard to the mesenterial plates as in 

 Pennatulids, showing a " Dorsalf ach " and " Ventralfach." No definite 

 protractor muscles were observed to be present. No regular arrangement 

 of the eight mesenteries with regard to the twelve so-called septa could 

 be found. Eight mesenterial filaments are present, two of which appear 

 to be longer than the others. In three individuals only of the single 

 colony examined were ova found — in one four ova, in the others only 

 one. The ova are attached to the mesenteries. The four ova were 

 attached to four separate mesenteries. No male elements were found. 

 The colonies are probably unisexual. The arrangement of the polyps in 

 the colony is somewhat irregular ; but the " Dorsalf ach " seems always to 

 be uppermost in the vertical plates of which the coral consists, the polyps 

 being thus placed back to back. 



On the Structure of Sarcophyton, sp. — An Alcyonarian was obtained at 

 the Admiralty Islands which agrees in every respect with Lesson's genus 

 Sarcophyton (M.-Edwards, Hist. Nat. des Corall. t. i. p. 22). A genus 

 called Sarcophyton is, however, cited by Claus as having been formed by 

 Sars. The Alcyonarian is mushroom-shaped. Two kinds of individuals, 

 zooids and polyps, compose the colony ; the stem is composed of large 

 tubes (" sinus"), the prolongations of polyp-cavities. The polyps offer no 

 marked peculiarities ; their retractor and protractor muscles are arranged 

 as in Pennatulids with regard to the mesenteries. They have two me- 



