338 ORDER CHOANO-FLAGELLATA. 



many as, or more than, one hundred individual zooids. With the exception of 

 C. pyriformis, it is further the only example, out of the nine known species of 

 the genus, that has been found in salt water, though doubtless future investigation 

 will reveal the existence of many additional forms. The species as here figured and 

 described was met with in November 1875, attached in great abundance to the 

 empty cells of Polyzoa and Sertularian zoophytes, taken from the marine tanks of 

 the Manchester Aquarium, at that time in the author's charge. As these zoophytes 

 were in the first instance derived from various remote localities, it is not possible to 

 fix the exact station on the British coast-line from whence they were originally 

 imported. The branching pedicle or zoodendrium of Codosiga cymosa varies con- 

 siderably in different colonies ; where a large number of zooids are present the 

 characteristic corymboid type is predominant, and the colony-stock as a whole con- 

 siderably resembles in external contour the corymbiform flower-spike or panicle of 

 the sea-lavender (Statice limonium). PI. III. Fig. 7, represents an abnormal 

 growth of this species in which the complete colony-stock presents in the arrange- 

 ment of its constituent zooids an aspect highly suggestive in miniature of the zoarium 

 of the polyzoic genera Aulopora or Hippothoa. This growth-form is produced by the 

 abnormal mode of gemmation. Usually the tree-like colony is formed by the 

 irregular dichotomous branching of the pedicle, the primary animalcules at the base 

 of these branches becoming obliterated or losing their individuality by their onward 

 growth. In this instance, however, each new bud, in taking its origin from the base 

 of its predecessor, has left the preceding one intact, while at the same time the 

 gemmation is much more sparse, and the pedicle to each individual is unusually 

 prolonged. As shown at Fig. 4, it mostly happens that all the animalcules com- 

 posing one large colony-stock, are so disposed as to face in the same direction, a 

 formula of growth remarkable for its symmetry and elegance. At PI. III. Fig. 6a 

 will be found delineated a zooid in which the collar is retracted and the body, after 

 throwing around it a hardened cyst-like investment, has divided itself into two equal 

 parts. This no doubt represents the initial stage of a further breaking up of the 

 entire body into sporular elements. As shown at Fig. 50, there appears to be a 

 tendency in this species to occasionally produce zooids of abnormal size. This 

 phenomenon is probably also connected with the function of reproduction, and is 

 suggestive of the like development, for reproductive purposes, of animalcules of 

 abnormal size, which obtains in the genus Zoothamnium, among the higher Peritri- 

 chous Infusoria. 



Codosiga grossularia, S. K. PL. II. FIGS. 10 AND n. 



Zooids subspheroidal, attached in small clusters, through the inter- 

 medium of short independent pedicles, to a simple or sparsely branching 

 main rachis. Length and diameter of bodies of animalcules 1-2500" ; height 

 of main rachis five or six to ten times the length of the supported zooids, 

 secondary branchlets not equalling or but slightly exceeding their diameter. 



HAB. Fresh water. 



This species may be easily recognized by the globose form of the bodies of the 

 separate zooids, all the remaining representatives of the genus hitherto met with 

 exhibiting a more or less ovate outline. The main stem remains undivided for 

 a considerable distance, and is sinuous, as in C. alloides. The secondary subdivisions 

 of the pedicle rarely exceed in length the diameter of a single animalcule, and 

 being given off in close proximity to one another, impart to the complete colony- 

 stock a considerable resemblance to a small bunch of currants. This species is 

 of rare occurrence, two or three isolated examples only having been so far met 

 with. At Plate II. Fig. n a colony-stock of three zooids only is represented, which 

 are protruding digitiform pseudopodia from their lateral peripheries in a manner cor- 

 responding to that which has been previously recorded of C. botrytis. The examples 



