April, 1922 a new type of bryozoan gizzard 159 



The new type of gizzard to be described has been discovered 

 in another family of the Ctenostomata, the Buskiidse, of which 

 the genus Biiskia Alder is the only representative. Alder (1856, 

 p. 156) failed to note the presence of a gizzard in B. nitens 

 and Hincks (1880, p. 532) also failed to discover it. Later 

 Hincks (1887, p. 127) described B. setigera from the Mergui 

 Archipelago, again failing to note the presence of a gizzard. 

 The s-mall size of the individual in Buskia (in B. armata the 

 length is .6 mm. and the breadth .2 mm.) and the much smaller 

 size of the gizzard in comparison with that in the Vesiculariidae, 

 together with the fact that it is divided into lobes, are respon- 

 sible, no doubt, for this failure to find it. 



In 1912 Osburn (p. 256) re-described Verrill's Vesicularia 

 armata under the name Hippuraria armata (Verrill). In his 

 original description Verrill (Verrill and Smith, 1874, p. 710) 

 had not noticed the gizzard in this species. Osburn figured and 

 described the gizzard for the first time (p. 256, PI. XXIX, Figs. 

 84a and 84b). See Figures 1 and 2. 



More recently Harmer (1915, pp. 85-89) has restudied the 

 genus Buskia and has found a gizzard in B. nitens and B. 

 setigera. If his figures (PI. 5, Figs. 10, 15 and 16), which are 

 small and not detailed, are to be relied on, the gizzard in these 

 species is of the same type as in the armata of Verrill. Harmer 

 indicates that armata belongs to the genus Buskia and is closely 

 related to B. setigera, a conclusion with which we are quite 

 ready to agree. There is reason for considering it a distinct 

 species, how^ever, for armata, as far as observed, does not 

 possess basal spines for the firmer attachment of the zocecium 

 and the zocecial wall is not perfectly transparent as described 

 by Hincks, but is of a yellowish horn color. Buskia armata 

 should be kept separate for the present at least, especially since 

 its distribution in the North Atlantic lies to the northward and 

 it tends to disappear toward the tropics. 



Osburn's description of the gizzard (1912, p. 256) is as 

 follows: "a small but distinct gizzard, not completely sur- 

 rounding the gut, but forming several rounded lobes, with 

 pointed teeth projecting into the cavity." The four lobes of 

 the gizzard, with a band of circular muscles, is shown by 

 Osburn in Plate XXIX, Figs. 84a and 84b. 



The nature of the gizzard lobes and their mode of formation 

 have been worked out by the junior author. The grinding 



