96 PEOCEEDINGS OP THE NATION" AL MUSEUM vol.72 



the poster and on one side only. The ovicell is large globular, 



porous, covering a large portion of the distal zooecium. 



,, J 4 ^ fA.a = 0.14-0.15 mm. 



Measurements. — Apertura^ ^ _ ._ 



^ I ta==0.12 mm. 



„ . {is = 0.60-0.75 mm. 



2^^""MZ3 = 0.30-0.40 mm. 



Variations. — The colonies have generally the aspect of hollow 

 tubes of a half centimeter in diameter, irregularly ramified, and of a 

 length measuring as much as 3 centimeters. These tubes are never 

 ancestrular. One of these colonies still had its base fixed on a small 

 shell and then developed, forming an arborescent ensemble. Although 

 living, as no trace of the alga was observed at the center of the tubes, 

 we suppose that the latter was very fragile and naturally was 

 destroyed during cleaning of the specimens. 



The avicularia are the most variable organs. Their beak is very 

 salient and at times perpendicular to the apertural plane. On certain 

 zooecia they are placed exactly on the frontal. They are generally 

 oriented obliquely toward the top of the colony, but this orientation 

 varies considerably according to the irregularity of the substratum 

 and of the budding; rarely the point is oriented toward the base. 

 Their length varies from one branch to another (0.20 mm. to 0.30 mm). 

 Whatever the orientation or size may be, the mandible is always low- 

 ered on the rimule. 



The zooecia of the external lamella are very often irregularly ori- 

 ented. The size of the frontal mucro is equally variable. 



Affinities, — This new species differs from ScJiiBopodrella isdbelleana 

 Smitt, 1873, in its elongated and nontransverse aperture, in the pres- 

 ence of a frontal mucro, and in its larger avicularia. 



The projections on the zoarial surface made by the umbo and by 

 the avicularia give it a prickly aspect which enables the species to be 

 rather easily distinguished. 



On specimens boiled in Javelle water the aperture shows the same 

 features as in Schizopodrella isahelleana; on each side of the rimule 

 there are two very small secondary indentations. 



Biology, — The avicularia are not zooecial but they are indeed oral 

 avicularia not only because their occurrence is constant but also 

 because the mandible in opening comes always in immediate con- 

 tact with the rimule. Their function remains mysterious but it 

 appears in connection with the hydrostatic system. 



The larva fixes itself on dead shells which the colony surrounds 

 in developing their many lamellae. If the shell is small the ensem- 

 ble must be very light and buoyant. But the colonies develop with 

 much more ease on shells already covered with algae or with radicles. 

 They encrust the latter, forming the curious tubes described pre- 



