BRITISH ASSOCIATION. 249 



viously described species of Steenstrupia : there can, therefore, be no 

 doubt that it is rightly referrible to that genus. I have taken the liberty 

 of naming this species after the distinguished author of " Parthenoge- 

 nesis." 



Concerning the development of these animals, our knowledge is still 

 insufficient. The production of Medusoids from hydraform zoophytes 

 has been ably investigated by Dr. T. Strethill Wright {vide his papers 

 in the " Edinb. New Phil. Journal"). To Mr. Peach we are indebted 

 for an interesting account of the curious metamorphosis of a zoophyte- 

 like animal, which he obtained in March, 1855, on an old valve of 

 Psammobia ferroensis. These creatures were of a hydra-like form, at- 

 tached to the shell by a short footstalk. The upper part was rather 

 inflated, and furnished with a slightly raised and rounded centre, from 

 which extended four long and four short leaf-like arms, each granulated 

 down the centre. The description of these anomalous animals can 

 hardly be reconciled with that of any known species of zoophyte. 



After a few days the form of the animals began to change, and they 

 subsequently became transformed into true naked-eyed Medusae : for a 

 full account of these changes, see Mr. Peach's paper and figures pub- 

 lished in the "Ann. JNat. Hist." for 1856. The Medusoids showed 

 some resemblance to Lizzia and Sarsia. The production of fixed po- 

 lypes from the ova of Tunis has been observed by Gegenbaur (" Compt. 

 Rendus," Sept. 1853). Mr. Hincks ("Ann. K H.," 1852) has described 

 the Medusoids of Campanularia volubilis. 



During the past summer I have repeatedly submitted living speci- 

 mens of Laomedeae to examination. The Medusoids of L. geniculates are 

 generated in the same manner as those of L. gelatinosa, observed by 

 Yan Beneden, namely, in the interior of the so-called ovarian capsules. 

 The Medusoids so produced speedily detached themselves, and moved 

 rapidly through the water. This is at variance with the account given 

 of the development of L. geniculates by Loven, who affirmed (" Wieg., 

 Archiv," 1857) that the Medusae-like bodies in this species never be- 

 come detached, but merely expanded at the summit of the ovigerous 

 capsules discharged ever in the form of ciliated gemmules, which sub- 

 sequently attached themselves, and developed into hydraform Zoophytes. 

 The researches of Loven are detailed with considerable accuracy, so 

 that there arises a difficulty as to the manner in which we are to explain 

 the occurrence of the reproductive zooids, under a twofold aspect, in the 

 same species. Perhaps it is due to difference of sex. The Medusoids of 

 L. dichotoma, as observed by Mr. Peach and the late Sir J. S. Dalyell, 

 were free and detached ; and the figure of Mr. Peach (in Johnston's 

 " Brit. Zoophytes," vol. i. p. 119) exactly coincides with the Medusoids 

 of Laomedea above noticed. It will be remembered that Sir J. S. Dal- 

 yell bestowed on these animals, the extraordinary name of Animalculum 

 tintinnabulum. In describing the development of any of the Campanu- 

 lariadae, writers should carefully note the specific characters of the Zoo- 

 phyte observed, as the British species of this group are not yet suffici- 

 ently known. Much yet remains to be done before our knowledge of 



