REPORT ON THE SIPHONOPHOR^E. 239 



more or less spirally convoluted ; it is sometimes regularly articulate, with equidistant 

 segmental constrictions (in Strobed ia and Forskedia, PI. IX. fig. 7, a) ; at other 

 times the annular constrictions disappear and the cylindrical or slightly com- 

 pressed stem is not articulate (in Forskaliopsis and Bathyphysa). Respecting the 

 composition of the cormidia and their attachment at the trunk, we distinguish in the 

 Forskalidas ordinate and loose cormidia ; the former occur in Strobalia, the latter in 

 the three other genera. 



The ordinate cormidia of Strobalia are similar to those of Stephanomia, Crystcdlodes, 

 Anthemodes , &c. Each cormidium is attached to a node of the trunk, or a constriction 

 of the stem, and composed of five different medusomes, three sterile (a siphonal, a 

 cystonal, and a palponal) and two fertile (a male and a female). The siphonal medusome 

 is composed of a pedunculate siphon, a tentacle, and a corona of bracts on the base of 

 the pedicle. The cystonal medusome consists of a cyston and a palpacle, surrounded 

 by a group of bracts. The palponal medusome is composed of a palpon with its 

 palpacle and a basal corona of bracts. The two sexual medusomes are represented by a 

 pair of gonodendra, which bear clustered gonophores, a male and a female. The 

 long internodes of the stem, between these ordinate distylic cormidia, are free and 

 covered only by small bracts. 



The loose cormidia of the other three genera of Forskalidse may be derived 

 from the ordinate cormidia of Strobalia by dislocation of the associated medusomes. 

 The axial trunk of the siphosome preserves in Forskalia the distinct articulation, whilst 

 this is lost in Forskaliopsis and Bathyphysa. The polymorphous medusomes which 

 compose the cormidia are here more or less separated, and the different persons and 

 their organs more or less scattered. In Forskalia sometimes each cormidium is 

 composed rather regularly of four separate and different medusomes, attached at 

 intervals to the succeeding internodes of the stem. The first medusome is a siphonal 

 one (with siphon and tentacle), the second a cystonal (with cyston and palpacle), the 

 third a palponal (with palpon and palpacle), and the fourth a sexual (with a sexual 

 palpon and a monostylic gonodendron). But in the larger corms of Forskaliopsis and 

 of Bathyphysa the number and succession of medusomes in each cormidium seems to 

 be variable and often perfectly irregular. 



Bracts. — The hydrophyllia or covering scales are always very numerous, and cover, 

 densely crowded, not only the stem of the siphosome, but also the long pedicles of the 

 single siphons, cystous, and palpons. Their number is even in the smaller species 

 several hundreds, and in the larger many thousands. The splendid Mediterranean 

 Forskaliopsis ophiura has more than five hundred siphons and on the pedicle of each 

 siphon more than a hundred bracts; the number of cystons and palpons, however, 

 amounts to two thousand to four thousand or more ; and since the pedicles of these 

 are also covered with bracts, the total number of the latter may amount to more than 



