BARGMANNIA REVISION 



A 



Fig. 10 Bracts of Bargmannia amoena sp. nov. Scale bars: A, B, C = 1 

 mm, D, E = 2 mm. 



together than on the first type, so that the distal end of the bract is 

 relatively narrow. One of the proximal pair of teeth is usually more 

 developed than the other, and on that side the lateral wall of the 

 proximal part of the bract often extends out as a rounded notch. 



Gastrozooid and tentacle (Figure 11 A, C). The largest 

 gastrozooids measure up to 10 mm in length. In the preserved state 

 they are suffused with a brown coloration with, in the largest 

 specimens, the basigaster having bright orange-red pigmentation. 

 The latter (Figure 1 1C, bg), typically, is cup-shaped, enclosing the 

 base of the stomach region, and is covered in large rounded ecto- 

 dermal cells. The stomach region (Figure 1 1C, s) appears relatively 

 thin and the endodermal hepatic villi can be seen within. The 

 proboscis region can be extended to some distance. 



The tentacle can be several centimetres in length. It is a simple, 

 narrow, unsegmented tube, bearing a haphazard and irregular arrange- 

 ment of the two sorts of small nematocysts that are also found on the 

 tentilla. In the present specimens, only a few tentilla, up to 10, 

 remain attached close to its base. In their preserved state, the tentilla 

 (Figure 1 1A) typically are highly contracted and are comprised of a 

 short pedicel; an irregularly twisted cnidoband; and, for the most 



61 



part, a regularly coiled terminal filament. The cnidoband is a simple 

 tube that, in life, is generally straight or slightly curved, and can 

 extend to a length greater than 0.5 cm. One side of the cnidoband 

 appears to consist of a primitive elastic strand. It is not tightly folded, 

 as is the case in some other physonect species, but a few pleats are 

 present. The other side of the tentillum is comprised of numer- 

 ous rows of small nematocysts of two types, as was the case in 

 B. elongata. These are ovoid, measuring 20 x 14 urn and 12x11 urn, 

 and occur in roughly equal proportions and possibly in alternat- 

 ing rows, although this could not be determined with certainty. 

 Similar nematocysts are found along the length of the terminal 

 filament. Again, it has not been determined whether these nemato- 

 cysts are the acrophores and desmonenes found in other physo- 

 nect siphonophores. At the proximal end of the cnidoband there is a 

 paired series of up to 26 stenoteles that measure 135 x 105 urn. 



SlPHOSOMAL TENTACLES AND BUDS (Figure 1 1 B, C). As several of 

 the siphosomal stems of the specimens examined remained relaxed, 

 it was possible to study the disposition of the siphosomal tentacles 

 and buds in detail. The primary siphosomal tentacle (Figure 1 IB, t) 

 is inserted midway between successive gastrozooids and can be 

 tightly coiled or extend to several millimetres in length. As in 

 B. elongata. its surface is covered in large ectodermal cells and there 

 is a paired series of nematocysts along one side. 



On each cormidium there are, at least, four solid bud-like struc- 

 tures, whose arrangement is sexually dimorphic. In the female 

 specimens (Figure 1 IB), the first bud (bl) lies a short distance distal 

 to the gastrozooid (gzl), while the second (b2) is inserted about one 

 quarter the length of the cormidium. The gonodendron is then 

 inserted between the latter and the central siphosomal tentacle (?). 

 The third bud (b3) lies a short distance distal to this tentacle, and the 

 last (b4) is inserted immediately proximal to the next gastrozooid 

 (gz2). In the male specimens (Figure 11C), the gonodendron is 

 situated immedietly distal to the gastrozooid. The first bud (bl) then 

 lies distal to the gonodendron at about one quarter the length of the 

 cormidium; that is approximately in the same position as the second 

 bud on the female specimens. The second bud lies immediately 

 proximal to the central siphosomal tentacle; and the third midway 

 between that tentacle and the next gastrozooid. The fourth, as in the 

 female specimens, is inserted immediately proximal to the next 

 gastrozooid. These arrangements pertain in the great majority of the 

 specimens examined, but in the largest ones another tentacle, and 

 possibly another bud, are found in close proximity to the fourth bud. 

 Usually, this tentacle is much smaller than the central tentacle, but 

 otherwise appears to be identical; including the double row of 

 nematocysts. 



Gonophore. (Figure 1 IB, C). As noted above, the degree of 

 sexual maturity of the specimens appears to be directly related to 

 their size, as assessed by the length of the nectophores. Thus in the 

 smallest specimens, at most, only gonophore buds can be seen. The 

 major group of medium sized specimens have better developed 

 gonophores, while the largest are obviously sexually mature. All 

 seven of the largest specimens are male. 



There is only a single gonodendron per cormidium. In male 

 specimens the gonodendron lies immediately distal to a gastrozooid 

 and proximal to the first siphosomal bud. The mature male 

 gonophores (Figure 1 1C, mg) measure up to 5.5 mm in length and 

 1.1 mm in diameter The female gonophores (Figure HB,/g) are 

 attached to the stem by a short stalk that is inserted approximately 

 midway between the second siphosomal bud and the central 

 siphosomal tentacle. Between one and six gonophores, in various 

 stages of development, are attached to it by short pedicels. Each 



